Alexandrian calendar

The Alexandrian calendar, created in the early centuries AD, was an ancient Egyptian reform of the Julian calendar. It divided the year into 12 months of 30 days each, plus an additional short month of 5 or 6 days, totaling 365 days. The calendar aligned closely with the solar year but did not account for the extra quarter-day, causing drift over centuries. Its primary purpose was for religious and administrative use, simplifying record-keeping by having a consistent, predictable cycle, while influencing later calendar designs.